MT-test3d-tools/t400.lua

86 lines
1.7 KiB
Lua

local t = {}
-- internal state
--- program counter (pc)
--- current instruction (ci) -- only passed from the environment to the emulator
--- stack (stack)
local function pop(s)
return table.remove(s,#s) or 0
end
local function push(s,v)
v=v or 0
s[#s+1] = v%4096
if #s > 16 then
table.remove(s,1)
end
end
function t.run(stab)
-- variables
local pc = stab.pc or 1
local ci = stab.cins or 0
local stack = stab.stack or {}
local rstack = stab.rstack or {}
local pci = 1
local rw = nil
local addr = 0
local dat = 0
-- instruction processing
if ci == 4095 then -- ppc
push(stack,pc)
elseif ci == 4094 then -- swp
a=pop(stack)
b=pop(stack)
push(stack,a)
pusk(stack,b)
elseif ci == 4093 then -- read
rw = "read" -- terrible IPC
addr = pop(stack)
elseif ci == 4092 then -- write
rw = "write"
addr = pop(stack)
dat = pop(stack)
elseif ci == 4091 then -- add
push(stack,pop(stack)+pop(stack))
elseif ci == 4090 then -- sub
push(stack,pop(stack)+pop(stack))
elseif ci == 4089 then -- jmp
pc = pop(stack)
pci = 0
elseif ci == 4088 then -- sez
if pop(stack) == 0 then
pci = pci + 1
end
elseif ci == 4087 then -- jez
local a = pop(stack)
if pop(stack) == 0 then
pc = a
pci = 0
end
elseif ci == 4086 then -- jsr
push(rstack,pc)
pc = pop(stack)
pci = 0
elseif ci == 4085 then -- ret
pc = pop(rstack)
elseif ci == 4084 then -- dup
local v = pop(stack)
push(stack,v)
push(stack,v)
elseif ci == 4083 then -- drop
pop(stack)
elseif ci == 4082 then -- hlt
rw = "halt"
else
push(stack,ci)
end
-- return stuff
stab = {}
stab.pc = pc + pci -- increment pc
stab.cins = 0
stab.stack = stack
stab.rstack = rstack
return stab, rw, addr, dat
end
return t